Magnesium sulfate is a hypertonic salt solution, with hypertonic, anti-inflammatory, decongesting effect. Its main mechanism of action is: i. Magnesium sulfate uses the effect of local high osmotic pressure to transfer the intracellular water to the extracellular, so that the local inflammatory edema of tissue cells in a dehydrated state, reduce the swelling of the lesion, to relieve swelling and pain. Second, magnesium sulfate can improve the activity of local lymphocytes, inhibit the reproduction of bacteria in the wound, increase the ability of granulation tissue to fight infection, which is conducive to inflammation subsidence. Third, magnesium sulfate can increase local blood circulation, improve the local tissue nutritional status, and promote wound healing. Clinically commonly used magnesium sulfate topical treatment of superficial phlebitis, dermatitis, acute lactation mastitis also has a significant therapeutic effect.